Commercially available training wheel assemblies typically comprise rigid brackets rigidly attached to the bicycle rear wheel axle. This rigidity inhibits the learning process. If the wheels are set low, the bicycle cannot be leaned at all, either to make a turn or just to compensate for riding on a cambered surface. If the wheels are set high the bicycle will lurch from side to side in an unnerving manner and, once the rider is leaning on one outrigger wheel, there is no restorative force acting to encourage the rider to regain the central equilibrium position.
A number of patents have been registered showing various designs, which attempt to address this problem. Most of the configurations proposed incorporate a suspension system based on the concept of a pivoted bracket supported by a spring, with the various fittings and fasteners required to retain the spring, whilst permitting the desired range of movement.
Some of these devices are quite complex and cumbersome, for example that disclosed in U.S. Pat. No. 4,810,000. In this design, the training wheels are raised and lowered by cables attached to the front wheel forks of the bicycle, which activates the cables as the front wheel is turned. As well as complexity and cost, this device has the added drawback that the movement of the training wheels is reliant upon correct adjustment of the mechanism, rather than simply responding to the normal lean of the rider.
Simpler, more viable designs typically employ a hinged bracket supported by a compression spring, plus the necessary fittings and fasteners. Typical of these devices are those disclosed in U.S. Pat. Nos. 5,064,213, 5,100,163 and 5,352,403.
These designs appear to be functional, however, since none appear to have been commercialized their principal drawback would seem to be cost to manufacture; they also have a “gadgety” appearance, which may not appeal to the market.
More importantly, the exposed coil spring design presents numerous pinch-points for trapping and injuring small fingers, which is a significant drawback.
The simplest design is that disclosed in U.S. Pat. No. 6,113,122 and previously in U.S. Pat. No. 5,707,069. It's main feature is that it combines the structural support of the outrigger wheel and the flexible spring action desired in the one element, namely a helically wound torsion spring.
This design appears to be functional and relatively cheap to manufacture. However, it may lack torsional rigidity about the vertical rod part of the member, allowing excessive fore and aft movement of the outrigger wheel. This would be especially so if the assemblies were installed back to front (ie. on the wrong sides), as the helical spring would then tend to open, rather than close.
The assemblies would need to be marked clearly “Left” and “Right” hand and would need to be installed correctly so. In addition, the steel torsion spring has virtually no inherent damping available to damp out unwanted oscillations or vibration.